This invention relates to an element selecting device having a function capable of selecting one of a plurality of optical elements provided on a frame and locating the selected one in an optical path; and, more particularly, to an element selecting device arranged so as to be smoothly moved in a predetermined plane having a positional relationship with the optical path.
For example, as one example of the above-optical element, an optical filter is considered which is capable of passing light corresponding to a predetermined wavelength.
Conventionally, in electronic copy machines which make copies employing so-called electrophotographic system and in image processing devices such as an image scanners which scan a character side of an original and read the image data as electric signals, devices having a function for separating the colors of original to make color copies and for obtaining signals corresponding to a plurality of colors have been known.
Various color separation methods including a method in which the character side of the original is irradiated by illuminating light corresponding to a specific wavelength have been generally considered. In many methods, one specific filter is selected from three types of filters, namely, red, green, and blue plus an ND filter which is included in most cases, and the selected filter is placed in an optical path from the character side of the original to a photoconductive drum or a light receiving element. The images corresponding to the original which pass through various filters are scanned or transferred. In the electronic copy machines, the passing light, having been passed through the various filters are developed, transferred, and fixed by utilizing cyan, magenta, and yellow toners so as to make color copies.
In the image processing device which places a selected filter from a plurality of filters in an optical path from the character side of the original to the light receiving element, a disk plate on which a plurality of filters are provided around the same circumference of the disk plate can be rotated about a shaft in parallel to the optical path so that the desired position on the circumference where the filters are provided matches the optical axis of the light being transmitted from the original to the light receiving element. By rotating the disk plate, the filters on the optical path are changed. Alternatively, a plurality of specific filters are provided on a filter frame in series and by matching the center of the filters with the optical axis, the filter frame can be moved in the direction where the filters are provided. Moreover, a plurality of filters are fixed around the rotating axis so that the filters are placed in parallel to the rotating axis and the axis is located in perpendicular to the optical axis. By turning the filters around the rotating axis, one of them can be selected and selectively located on the optical path. In addition, the filters are often larger circles than image circles on an optical path where they are placed in any structure.
However, in these conventional structures as described above, due to an installation of the device including the filters and a motion of filter conversion mechanisms for placing the desired filter on the optical path, wide spaces are required, which prevent the entire device from being miniaturized.
In other words, for the device which utilizes a disk plate on which a plurality of filters are provided around the same circumference, a space which is two times or more the diameter of the filters is required in the vertical direction. On the other hand, for the device which moves the filter frame where the filters are provided in a straight line, a space which is equivalent to a motion stroke on both the left and right sides in the moving direction of the filter frame (for example, the space for three filters is required in case that the four filters are provided) is required.
In other structures, wide installation and moving space are also required.